Related Experiment Video
Updated: May 29, 2026
10:52
Direct Imaging of Laser-driven Ultrafast Molecular Rotation
Published on: February 4, 2017
Direct observation of a propagating spin wave induced by spin-transfer torque
M Madami1, S Bonetti, G Consolo
1CNISM, Unità di Perugia and Dipartimento di Fisica, Università di Perugia, Via A. Pascoli, I-06123 Perugia, Italy. marco.madami@fisica.unipg.it
Nature Nanotechnology
|August 30, 2011
Summary
Researchers observed propagating spin waves from nanoscale spin torque oscillators in magnetic films. This provides direct evidence for spin wave propagation, crucial for future spintronic applications.
Area of Science:
- Spintronics
- Condensed Matter Physics
- Materials Science
Background:
- Spin torque oscillators (STOs) generate spin waves in magnetic films.
- Potential applications require propagating spin waves, but direct evidence has been limited.
- Nanoscale electrical contacts offer control and broadband operation for STOs.
Purpose of the Study:
- To directly observe and characterize propagating spin waves launched from STOs.
- To provide evidence for spin wave propagation in extended magnetic films.
- To explore the tunability and propagation distance of these spin waves.
Main Methods:
- Utilized spin torque oscillators with nanoscale electrical contacts.
- Employed wave-vector-resolved micro-focused Brillouin light scattering (μFB LS) for direct observation.
- Performed micromagnetic simulations for theoretical validation.
Main Results:
- Directly observed propagating spin waves in an extended Permalloy film.
- Demonstrated tunable spin wave frequencies propagating over several micrometres.
- Micromagnetic simulations quantitatively reproduced experimental findings.
Conclusions:
- Spin torque oscillators with nanoscale contacts can launch propagating spin waves.
- This work provides crucial evidence for spin wave propagation, enabling new spintronic device designs.
- The findings support the use of STOs for applications requiring long-range spin wave transport.
Related Concept Videos
01:08Spin–Spin Coupling Constant: Overview
In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
01:13Torque On A Current Loop In A Magnetic Field
The most common application of magnetic force on current-carrying wires is in electric motors. These consist of loops of wire, which are placed between the magnets with a magnetic field. When current flows through the loops, the magnetic field applies torque, which causes the shaft to rotate, thus converting electrical energy to mechanical energy.
Consider a rectangular current-carrying loop containing N turns of wire, placed in a uniform magnetic field. The net force on a current-carrying loop...
Consider a rectangular current-carrying loop containing N turns of wire, placed in a uniform magnetic field. The net force on a current-carrying loop...
01:08NMR Spectroscopy: Spin–Spin Coupling
The spin state of an NMR-active nucleus can have a slight effect on its immediate electronic environment. This effect propagates through the intervening bonds and affects the electronic environments of NMR-active nuclei up to three bonds away; occasionally, even farther. This phenomenon is called spin–spin coupling or J-coupling. Coupling interactions are mutual and result in small changes in the absorption frequencies of both nuclei involved. While nuclei of the same element are involved in...
01:17Spin–Spin Coupling: One-Bond Coupling
Coupling interactions are strongest between NMR-active nuclei bonded to each other, where spin information can be transmitted directly through the pair of bonding electrons. While nuclei polarize their electrons to the opposite spins, the bonding electron pair has opposite spins. Configurations with antiparallel nuclear spins are expected to be lower in energy. When coupling makes antiparallel states more favorable, J is considered to have a positive value. The one-bond coupling constant, 1J,...
01:30Propagation Speed of Electromagnetic Waves
Electromagnetic waves are consistent with Ampere's law. Assuming there is no conduction current Ampere's law is given as:
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...